Hall potential

Measurements of photoconductivity and of the Hall potential [367] are accurate and unambiguous methods of detecting electronic conduction in ionic solids. Kabanov [351] emphasizes, however, that the absence of such effects is not conclusive proof to the contrary. From measurements of thermal potential [368], it is possible to detect solid-solution formation, to distinguish between electronic and positive hole conductivity in semi-conductors and between interstitial and vacancy conductivity in ionic conductors. 

Consider the following experiment A current having a current density is passed through a metal strip in the x direction simultaneously a magnetic field B is applied in the z direction. Two probes A and A are placed on opposite sides of the strip (Fig. 31.1). The magnetic field, indicated by the dashed circle in Fig. 31.1, deflects the electron stream in the metal with the result that an electrical fleld Ey develops across the width of the strip and produces a potential difference the Hall potential, between the two probes A and A. ... 

Finally, there is the curious result that if the electrons that carry the current are in levels near the top of a band, then the field pushes the electrons in the wrong direction wrong in the sense that they are accelerated in the direction opposite to the usual one. These electrons behave as if they were positively charged. This happens with zinc and cadmium as well as a number of other metals. The effect is detected in the Hall experiment the Hall potential for these metals has the opposite sign when compared with a metal such as copper. 

Measurement of the magnitude and sign of the Hall potential in semiconductors enables us to distinguish experimentally between p- and n-type semiconductors, and to determine, knowing k, the number and mobility of the carriers. 

Hall effect If a current (I) is passed through a conducting crystal in a direction perpendicular to that of an applied magnetic field (H), the conductor develops a potential (V) between the faces which are mutually perpendicular to both the direction of the current and the magnetic field. This is known as the Hall effect the magnitude of the potential difference is given by... 

Latimer, W. M. 1952, Oxidation Potentials, Prentice-Hall, Englewood ClifTs, NJ Lednicer, D. Mitscher, L. A. 1977 dt 1980, The Organic Chemistry of Drug Synthesis, Vols. I IT, Wiley New York London... 

W. M. Latimer, The Oxidation States of the Elements and Their Potentials inMqueous Solutions, 2nd ed., Prentice Hall, Inc., Englewood Cliffs, N.J., 1952,... 

Uses. In spite of unique properties, there are few commercial appUcations for monolithic shapes of borides. They are used for resistance-heated boats (with boron nitride), for aluminum evaporation, and for sliding electrical contacts. There are a number of potential uses ia the control and handling of molten metals and slags where corrosion and erosion resistance are important. Titanium diboride and zirconium diboride are potential cathodes for the aluminum Hall cells (see Aluminum and aluminum alloys). Lanthanum hexaboride and cerium hexaboride are particularly useful as cathodes ia electronic devices because of their high thermal emissivities, low work functions, and resistance to poisoning. 

The values given in the following table for the heats and free energies of formation of inorganic compounds are derived from a) Bichowsky and Rossini, Thermochemistry of the Chemical Substances, Reinhold, New York, 1936 (h) Latimer, Oxidation States of the Elements and Their Potentials in Aqueous Solution, Prentice-Hall, New York, 1938 (c) the tables of the American Petroleum Institute Research Project 44 at the National Bureau of Standards and (d) the tables of Selected Values of Chemical Thermodynamic Properties of the National Bureau of Standards. The reader is referred to the preceding books and tables for additional details as to methods of calculation, standard states, and so on. 

Song et al. [16] reported results relative to a four-point resistivity measurement on a large bundle of carbon nanotubes (60 um diameter and 350 tm in length between the two potential contacts). They explained their resistivity, magnetoresistance, and Hall effect results in terms of a conductor that could be modeled as a semimetal. Figures 4 (a) and (b) show the magnetic field dependence they observed on the high- and low-temperature MR, respectively. 

Hall, R. et al., 1983, Control Rod Trip Failures Salem I, The Cause, The Response and Potential Fixes, ANS Trans. Topical Meeting, Jackson Hole, WY, April. 

An alternative analysis of eolloidal interaetion and stability based on elassieal solution thermodynamies has been proposed independently by Hall (1972) and Ash etal. (1973) and the praetieal implieations with partieular interest in the effeets of polymers and surfaetants has been diseussed by Pethiea (1986). In this theory, the forees between partieles are governed in a straightforward way by the adsorptions of the eomponents of the system and their dependenee of partiele separation and ehemieal potentials (whieh are defined by the eomposi-tion) aeeording to the equation... 

H2CO potential energy surface 191 Hall 263 Hamiltonian 254 Handy 117... 

Latimer, W. M., Oxidation States ofthe Elements and Their Potentials in Aqueous Solutions, Prentice-Hall, New York, 294 (1950)... 

Latimer, W. L., Oxidation Potentials, Premice Hall, New York, 191 (1961)... 

Hall, G. G., Trans. Faraday Soc. 49, 113, Calculation on the ionization potentials of some substituted ethylencs."... 

Kabanov [351] has provided an excellent review of the application of measurements of electrophysical effects in studies of the thermal decomposition of solids, including surveys of electrical conductivity, photoconductivity, dielectric measurements and interface (contact), Hall and thermal (Seebeck) potentials. Care must be exercised in applying the results obtained in such studies to the interpretation of data for thermal decomposition in the absence of an applied electric field since many examples have been given [352] in which such a field markedly influences the course of decomposition. 

Chromium, molybdenum and tungsten thermodynamic properties, chemical equilibria and standard potentials. I. Dellien, F. M. Hall and L. G. Hepler, Chem. Rev., 1976, 76, 283-310 (400). 

Latimer, W., Oxidation Potentials, 2nd ed. Prentice-Hall, Englewood Cliffs, New Jersey, 1961. 

Weiner CP, Mason CW, Buhimschi C, Hall G, Swaan PW, Buhimschi I. Changes in uterine GTPase activity are not consistent with changes in expression of Ga subunits of heterotrimeric G-proteins A potential mechanism for myometrial quiescence. Society of Gynecological Investigation. Los Angeles, CA, 2005. 

The E-state indices are atomic descriptors composed of an intrinsic state value I and a perturbation AI that measures the interactions with all other atoms in a molecule. The Kier-Hall electronegativity is the starting point in the definition of the intrinsic state of an atom, which encodes its potential for electronic interactions and its connectivity with adjacent atoms. The intrinsic state of an atom i is [19, 21] ... 

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